The present invention relates to photographic processing apparatus and is more particularly concerned with processing apparatus having at least one spiral processing path.
Photographic processing apparatus are well known in which the material being processed is transported along a helical path. Examples of such apparatus are described in Research Disclosure, November 1980, No. 19948, U.S. Pat. No. 3,968,510, U.S. Pat. No. 3,827,617, U.S. Pat. No. 3,823,859, U.S. Pat. No. 3,780,637, U.S. Pat. No. 4,025,937, U.S. Pat. No. 4,311,380 and EP-A-0 274 625.
The arrangement described in U.S. Pat. No. 3,827,617 comprises a helical web or film path processing device in which counteracting spools generate a force on the film which counteracts the normal tracking force generated as the film approaches a spool in a direction which is not perpendicular to the spool axis. The tracking force causes the film to climb the spool flanges, twist and fold over causing damage to the film.
The arrangements disclosed in Research Disclosure, November 1980, No. 19948 and U.S. Pat. No. 4,025,937 relate to porous conduit processors in which a transport strip or web is helically wound around the conduit. The material to be processed is inserted between the conduit and the transport strip or web, and is transported along the conduit with the strip or web.
U.S. Pat. No. 3,968,510 discloses another conduit arrangement in which a web to be processed is transported in a helical path. In this arrangement, the web is transported either by rollers or belts so that it is deflected by a helical rail or band wrapped around the conduit or by axially spaced radially extending protuberances which deflect the web along a helical path.
In U.S. Pat. No. 3,780,637, processing apparatus is disclosed in which a screw member having a helically disposed rib is utilized for retaining a flexible strip of photographic material for processing. The screw member is supported by a frame and is rotated about its axis when immersed in processing solution in a tank associated with the frame.
U.S. Pat. No. 3,823,859 discloses a processing rack which comprises a series of spools over which a web to be processed is threaded in a helical path. The spools are arranged in a tray having a plurality of semi-cylindrical cavities arranged in parallel side-by-side relation.
Apparatus for processing dental X-ray film is described in U.S. Pat. No. 4,311,380. The apparatus comprises a horizontally disposed processing chamber in which fluid retaining tanks are formed by lower portions of spiralling revolutions. The sidewalls of the chamber have grooves along which the film to be processed is driven through the chamber.
A processing device is described in EP-A-0 274 625 in which a plurality of long actuated guide forming elements are arranged in a processing liquid bath in a longitudinal direction. The material to be processed is transported through the processing liquid both along a helical guide path formed by the arcuated guide forming elements.
In all of the arrangements described above, the material being processed is transported in a longitudinal direction along a helical path. In each case, the apparatus is relatively bulky.
Furthermore, in some cases, means are arranged along the helical path to transport the material being processed along that path.
It is therefore an object of the present invention to provide photographic processing apparatus having a spiral processing path which is compact and does not suffer from the disadvantages mentioned above.